feat(launcher): Tauri desktop launcher for multi-org Studio

[vibegui]

What is this contribution about?

Adds apps/launcher, a lightweight cross-platform (macOS/Windows/Linux) Tauri v2 desktop launcher that renders the hosted Deco Studio in native OS WebViews — one window per org, all sharing a single login — so you can keep several orgs open at once without the memory footprint of a browser per org. It talks only to the hosted backend (configurable via DECO_STUDIO_URL; no local mesh/Postgres/NATS), and ships an app menu + system tray, single-instance focus, window-state and session restore, and per-window org titles ({org} - Deco Studio). The package is fully decoupled from apps/mesh (imports no app code) and is excluded from the root Bun workspace ("!apps/launcher") so a normal bun install doesn't pull the Tauri CLI / Rust toolchain.

Screenshots/Demonstration

N/A — native desktop windows; run locally to see (see How to Test).

How to Test

1. cd apps/launcher && bun install
2. bun run dev (requires Rust + Cargo)
3. Expected: a native Deco Studio window opens against studio.decocms.com; log in once, then ⌘/Ctrl+N opens more windows that share the session; the tray lists recent orgs; quitting and relaunching reopens your org windows with titles like deco - Deco Studio.

Migration Notes

None. Root bun install is unaffected (the launcher is excluded from the workspace and built with its own toolchain). Known follow-up: validate OAuth inside the WebView (Google may reject embedded WebViews — a desktop UA is set as the first mitigation; see apps/launcher/README.md).

Review Checklist

• PR title is clear and descriptive
• Changes are tested and working
• Documentation is updated (if needed)
• No breaking changes

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Summary by cubic

Adds a cross-platform Tauri desktop launcher that opens the hosted Deco Studio in native OS WebViews, one window per org, sharing a single login. Improves multi-org workflows with lower memory than browser tabs, plus session restore and tray/menu controls.

• New Features

  • New apps/launcher (Tauri v2) using the system WebView; each org opens in its own window.
  • Shared session across windows and per-window titles like "{org} - Deco Studio".
  • App menu and system tray with New Window and recent orgs; Cmd/Ctrl+N; single-instance focus.
  • Window geometry + session restore; reopens last org windows on launch.
  • Hosted-only backend (configurable via DECO_STUDIO_URL), no local mesh/Postgres/NATS; remote windows are sandboxed (no Tauri IPC). Package is decoupled and excluded from the root workspace; @tauri-apps/cli is a local devDependency.

• Bug Fixes

  • Added a no-op check script in apps/launcher/package.json so bun run --workspaces check succeeds even though the launcher is excluded from the root workspace.

^{Written for commit 95af06e. Summary will update on new commits.}